Clearly you do not operate professionally then!
Cones are handy for setting up a cordon (along with the tape) for separating the operations area from civilians.
Signage is pretty much a must have for UAV operations now days (along with reflective jackets preferable with company name on)
Up to date air chart/sectional overlays are a given and much more reliable and accurate than any iPhone/Android appy thing, other than products like Sky Demon or Sky Vector etc with the correct overlays.
Anomometer is a vital piece of gear for assessing wind velocity and making sure you are operating both within your aircrafts operational limits and also your own ops manual limitations.
First aid kit (and fire extinguisher are sensible precautions?)